Torque wrench



April 9, 1946. T. o. RUEB TORQUE vWRENCH Filed-Feb. 21, 1944 NSN Patented Apr. 9, 1946 2,398,330v `roRQUE WRENCH isfheodore..0.eRi51eb, Chicago, Ill., assigniorv to'ilhc 'f tion-of Delaware* This? inventionis aanwrenchi. adapted r flirtl the usual purposes and providedwith:means whereby it rmayi'betsetitofgive any desiredtorquefto vbe applied '.toalnut;Ioiolt,1o1rtheflike?` It "has been Vfound to be. highly. objectionable inl-,many instances; and particularlylr in: connection-T# With'- the tightening of cyli'nd'erwhead's;v to apply unequalpressure on the diierentI-'studslornuts for; to apply excessive pressurethereom Torque measuringA Wrenches havey heretofore been, proposed .and used YW-hereby the'operatonb`yobserving" alsc'alefon lth'e 1Wrench,.

may measurethe amountf of'itorquewhich is being applied` These:` vvrenchesf arerobjectionable inzthat it' requires the operator to Watch the gage and to Vstoppull'ing ati the desired time, .thus leav ing it to the skill of the operator tofdeterminef when the proper torque has been applied.` In many' instances; l it vmay l"also b'e difficult forN him to observe the scalelwlienthe nutsfor screws are in confined or out of*thevvayfplz`ices.V

In accordanceswith the presentinvention;` I" provide means wherebyf the-'Wrench "mayrbe :set` to." give a predetermined* torque andxwhen'such" torque or strain is reached; the'wrench :will slip or fthe. "handle turned without 'Lexertingz any2 fur-l therr or excessive."pressure.V Forzthis` freason, the Wrench'may be `used onnuts whichare `more or less hidden ormay yIde 'used in ,more-.or less dark* places where it .Wouldfbe impossible for 'inconvene ient to see the gagegandfthe:operatonwill: knoW thatY when the handle slips; .the :propel-for exact stress will; havenfbeen'V applied"v to;` the part being turned.

Thef objects of 'this invention arezto yprovidean improved@ Wrench.- off' the kind indicated. which to provide aA wrench having: affrictioni plate clutch fon-transmitting torque .tothe"Work4 piece toiprovidezfa wrench: hai/ingaat clutch';for,.'transmittingr worlc-z torquer to thezworkfA piece; and;` hydraulic pressure i meansvfor regulatingY the e: amount of f strain rwhicnmayf be transmitted by the =ic1utch;

to"-providea LWrench `having hydraulicor liquidi operated V mean-s for "*measurng'f andi controllingA theetorque; "to'provlde:` novel means.` for regulatingtheiluidzpressure; ,and to provide isu'chzotherl advantagesand iimprovements: as twill appearzin' the f 'following-ly description;r

Ina-.the accompanying?drawingllustrating: this` invention;`

Fig. 1 is a plan View;

projection I I with'aninwardly' extendingpangef or shoulder.;` I 2 at-.thef end .thereof which defines-ai central openingl I3:` Aihushing-Ilifflts-closelygini the projection.: I I anditerminates fatga= short dis-d tance from-the ange. I2.' This-bushingg is prefg-` erably made fof .fsome `special` steel-:or Aalloy rwhich may `be Vhighly finished -orlpollsh'edz AxvvasherlflSN tsbetween the end `of the .bush-ingandtheange: The bushinghas an outwardly extendinglfannue lar lia-nge IBthat rests onthe innerrsurface-rof theibottom Ii'l, thefarrangement beingysuchzthat there will be a tight closure betweerrthevbushingr and .otherparts so that r there ,will berno, leakage. A l short shaft Lorl driven member I'Iis-l rotatablyr mounted in the sleeve or bushing Maand yis fpref 1j erablgy lapped or-nishedtomake anlextreniely` tight l t therewith. This. shaftv may t have#` an angular 'extension I8 :tocoactwith Wrench'sockets I lvor` may be otherwise: arranged lto connect Withz the -parts1to beiturned." l

Theinner end of Ithe shaft .II has an extension 2l! which is serrated `or-knurled to `makea1 tight` fit with a i collar 2 I which. engagestherewithrand which; abuts' against` theupper. surfacefoffthe flange-I6; The outer surfacefofvthe-collar 2I has a pluralityV of. longitudinal ribs-22 which engage with correspondingly shapedi-slotslor recessesf523: in` frictionclutch plates or discs-.24: l as 'shownfin Fig. `5. A plurality of; such;clutch,.,plates:are.;

preferably provided" tov coact: withinterniedia'tel peripheral. recesses 32. ,for engagement: Withi the:

ribs 29.. This .platef has noxcentral. openingfland servesssomewhat :asa-v pistomfor :transmittingthe hydraulic'pressure" to the: otherlclutch plates.

A ring 33 is threaded to engage with corresponding threads 34 in the head 8 and is positioned above the plate 3|. This ring has a plurality of radial channels 35 in its lower face to permit the fluid to pass outwardly to its outer periphery. The head or cylinder 8 is closed at the top by a cover 35 that fits closely in the bore that is slightly enlarged above the ring 33 to provide a shoulder for receiving the cover. The cover is fastened in position by an adapter ring 31 having threads 38 for engagement with corresponding threads in the upper end of the head 8.

A gasket or sealing material 39 makes a tight closure between the adapterz and the cover and the inner surface of the'head. n

'Ihe cover 36 has a central threaded hole 48 for receiving the stem or connector 4l of a pressure gage 42 which is held in position and protected by the adapter ring 31 as shown. This pressure gage is of any ordinary or preferred construction and has the usual hand 43 'which coacts with a scale 44 to register pressure, the scale being preferably calibrated to indicate foot pounds.

' The Yprojection or handle portion 9 has a cylinder 45 which is connected by means of a hole 46 with the interior of the head 8 below the cover` 36. A vertical channel 41 is also provided so that the fluid may pass freely into the compression chamber 48V between the cover 36 and the clutch plate3l.' `A piston 49 engages with the cylinder 45 and has an enlargedV outer end portionf=50 whichisv provided with fine vthreads 5l for engagement with similar threads 52 in the enlarged bore 53 which extends outwardly from the cylinder'. The piston is provided at its inner end with the usual leather washer 54 which is held inposition by a screw 55 that has an enlarged head tting in the cupped portion of the leather 'to expand the same. This screw engages with a tapped hole 56 and has a slot in its inner end so that it may be engaged by a screw driver inserted through said hole for tightening the same. It is held in tightened position by a lock screw 51 which is also threaded to iit in the tapped hole 56.

` The piston 49 has a slip fit driving connection with a rod 58 by means of which it is turned. This connection comprises a hexagonal socket 59 in the end of the piston member which is engaged by the correspondingly shaped end portion Bllof the rod 58.` The rod is mounted in the handle 6I which has a threaded end 62 that engages with the correspondingly threaded enlarged portion 63 of the handle portion 9. The handle 6I is preferably grooved or corrugated as shown at 64 to provide a suitable grip. The outer end of the rod 58 is securely connected to a knob or button 65 as by means of a pressed fit so that it maybe turned by such' knob. The knob has a reduced portion 66 that rotatively engages with the end of the handle 6| and these parts are held against ylongitudinal movement by any suitable means suchas a spring ring 61.

When the wrench is to be prepared for use,fthe cylinder and compression chamber are lled with any suitable liquid such as oil, and the pressure gagescrewed into position and fastened by its adapter ring. The gage is preferably calibrated in foot Ypounds which may be done by attaching an arm and`weight or weights to the shaft or stem l1 and turning the knob 65 until suiiicient pressure is developed in the pressure chamber to cause the clutch to hold such weight. After the gage scale has been calibrated, all that is necessary for the operator to tighten a nut to a predetermined degree is to set the scale to the desired point. Then when the handle is turned for tightening the nut, it will be tightened to the predeermined amount at which point the clutch will slip and prevent any further strain on the nut. In this way, all of the nuts in a group, as for instance, those used in connection with a cylinder head may be tightened to exactly the same degree. The friction plates or discs of the clutch are preferably lapped until they are very smooth and the contact of such lapped surfaces will cause a certain amount of friction which, of course, is

increased or decreased by the hydraulic pressure.

The ring 33 fits sufficiently close to the pressure plate V3| to prevent undue separation of the clutch members while at the same time permitting suicient freedom for them to act in the desired manner. The channels'35 and the grooves around the clutch plates will permit a limited amount of oil to pass down around the plates and prevent their becoming too dry for emcient operation and also to prevent rusting of the same.

From this description, it will be apparent that my improved Wrench may be made so that it will be particularly sturdy and durable and will pro-` vide means whereby any desired torque may be given to a` work piece and further turning will be prevented by the slipping of the clutch.

While I have shown and described a preferred form ,of my invention, changes may be made in they details of construction or in the arrangement of the parts in order Yto adapt the same for different conditions or uses, and therefore I do not wish to be limited to thefparticular construction shown and `described except as specified in the following claims.

I claim': I l.

l. A torque measuring wrench, comprising a cylindrical head, a multiple vdisc clutch mounted in said head,V a work engaging member rotatably mounted in the head and driven by said clutch, said head having a compression chamber for receiving liquid for applying pressure to the clutch. apressure gage connected with the chamber for measuring the pressure, a handle extending outwardly from the head, a pump in the handle having a passageway leading to the compression chamber, and means for actuating the pump to regulate the pressure on the liquid which is in the pump and compression chamber.

2. A torque wrench comprising a head having a fluid chamber therein, a hydraulic pressure gage carried by said head, a friction `plate clutch mounted in the head, uid in the chamber for actuating the clutch and also being in communication with the gage, work driving means carried by the headand actuated by said clutch, a handle for turning the head and pressure means within the handle communicating with the pressure chamber for placing pressure on the fluid.

3. In a hydraulic torque wrench, the combination of a head having an annular chamber therein, a handle extending laterally from the head. having a cylinder communicating with the chamber, a piston coacting with the cylinder, fluid in said chamber and cylinder to be compressed by said piston,v means carried by the handle for actuating the piston, a friction plate clutch mounted in the head and adapted to be acted upon by the fluid in the chamber, a pressure gage connected with the chamber for indicating the pressure therein, a shaft rotatably mounted in the head and connected with the clutch whereby it may be turned, and means for connecting the shaft with a part to be turned.

4. In a torque wrench, the combination of a head having an annular chamber therein, a pressure gage connected with said chamber, a multiple disc elutch'mounted in the head below the chamber, a stem rotatably mounted in the head and driven by said clutch, a pressure plate forming one wall of the chamber and coacting with the clutch plates to transmit pressure thereto, a handle extending from the head and having a cylinder formed therein, a passageway leading from the cylinder to the chamber, uid in the chamber and cylinder, a piston having threaded engagement with the inner wall of the handle, a rod extending outwardly through the handle and having a slip driving connection with the cylinder, a knob secured to the end of the rod and rotatably connected with the hande, and means for preventing longitudinal movement of the knob with respect to the handle.

5. A device, as per claim 4, in which the piston is provided with a leather` washer, a screw engaging with a central threaded hole in the piston and having a head for expanding the washer, said screw having a slot on its inner end for turning the same, and a set screw also engaging with said threads for fastening the first named screw in position.

6. A torque wrench, comprising in combination, a head having a chamber therein, a handle extending from the head, having a cylinder communicating with the chamber, a piston coacting with the cylinder, fluid in said chamber and cylinder adapted to have pressure applied thereto by said piston, means for actuating the piston, a friction plate clutch mounted in the head and adapted to be controlled by the Huid in the chamber, the surfaces'of the plates of said clutch being smoothly finished to insure close contact, a pressure gage connected with the chamberA for indicating the pressure therein, a shaft rotatably mounted in the head and operatively connected with the clutch and adapted to beconnected with the part to be turned by the wrench.

- THEODORE O. RUEB. 

